I'm using ONE like this (Java, Hector): ConsistencyLevel consistencyLevel = new ConfigurableConsistencyLevel(); consistencyLevel.setDefaultReadConsistencyLevel(HConsistencyLevel.ONE); consistencyLevel.setDefaultWriteConsistencyLevel(HConsistencyLevel.ONE);
Michael Kjellman wrote > Are you writing with QUORUM consistency or ONE? > > On 11/27/12 9:52 AM, "Sergey Olefir" < > solf.lists@ > > wrote: > >>Hi Juan, >> >>thanks for your input! >> >>In my case, however, I doubt this is the case -- clients are able to push >>many more updates than I need to saturate replication_factor=2 case (e.g. >>I'm doing as many as 6x more increments when testing 2-node cluster with >>replication_factor=1), so bandwidth between clients and server should be >>sufficient. >> >>Bandwidth between nodes in the cluster should also be quite sufficient >>since >>they are both in the same DC. But it is something to check, thanks! >> >>Best regards, >>Sergey >> >> >>Juan Valencia wrote >>> Hi Sergey, >>> >>> I know I've had similar issues with counters which were bottle-necked by >>> network throughput. You might be seeing a problem with throughput >>>between >>> the clients and Cass or between the two Cass nodes. It might not be >>>your >>> case, but that was what happened to me :-) >>> >>> Juan >>> >>> >>> On Tue, Nov 27, 2012 at 8:48 AM, Sergey Olefir < >> >>> solf.lists@ >> >>> > wrote: >>> >>>> Hi, >>>> >>>> I have a serious problem with counters performance and I can't seem to >>>> figure it out. >>>> >>>> Basically I'm building a system for accumulating some statistics "on >>>>the >>>> fly" via Cassandra distributed counters. For this I need counter >>>>updates >>>> to >>>> work "really fast" and herein lies my problem -- as soon as I enable >>>> replication_factor = 2, the performance goes down the drain. This >>>>happens >>>> in >>>> my tests using both 1.0.x and 1.1.6. >>>> >>>> Let me elaborate: >>>> >>>> I have two boxes (virtual servers on top of physical servers rented >>>> specifically for this purpose, i.e. it's not a cloud, nor it is shared; >>>> virtual servers are managed by our admins as a way to limit damage as I >>>> suppose :)). Cassandra partitioner is set to ByteOrderedPartitioner >>>> because >>>> I want to be able to do some range queries. >>>> >>>> First, I set up Cassandra individually on each box (not in a cluster) >>>>and >>>> test counter increments performance (exclusively increments, no reads). >>>> For >>>> tests I use code that is intended to somewhat resemble the expected >>>>load >>>> pattern -- particularly the majority of increments create new counters >>>> with >>>> some updating (adding) to already existing counters. In this test each >>>> single node exhibits respectable performance - something on the order >>>>of >>>> 70k >>>> (seventy thousand) increments per second. >>>> >>>> I then join both of these nodes into single cluster (using SimpleSnitch >>>> and >>>> SimpleStrategy, nothing fancy yet). I then run the same test using >>>> replication_factor=1. The performance is on the order of 120k >>>>increments >>>> per >>>> second -- which seems to be a reasonable increase over the single node >>>> performance. >>>> >>>> >>>> HOWEVER I then rerun the same test on the two-node cluster using >>>> replication_factor=2 -- which is the least I'll need for actual >>>> production >>>> for redundancy purposes. And the performance I get is absolutely >>>>horrible >>>> -- >>>> much, MUCH worse than even single-node performance -- something on the >>>> order >>>> of less than 25k increments per second. In addition to clients not >>>>being >>>> able to push updates fast enough, I also see a lot of 'messages >>>>dropped' >>>> messages in the Cassandra log under this load. >>>> >>>> Could anyone advise what could be causing such drastic performance drop >>>> under replication_factor=2? I was expecting something on the order of >>>> single-node performance, not approximately 3x less. >>>> >>>> >>>> When testing replication_factor=2 on 1.1.6 I can see that CPU usage >>>>goes >>>> through the roof. On 1.0.x I think it looked more like disk overload, >>>>but >>>> I'm not sure (being on virtual server I apparently can't see true >>>> iostats). >>>> >>>> I do have Cassandra data on a separate disk, commit log and cache are >>>> currently on the same disk as the system. I experimented with commit >>>>log >>>> flush modes and even with disabling commit log at all -- but it doesn't >>>> seem >>>> to have noticeable impact on the performance when under >>>> replication_factor=2. >>>> >>>> >>>> Any suggestions and hints will be much appreciated :) And please let me >>>> know >>>> if I need to share additional information about the configuration I'm >>>> running on. >>>> >>>> Best regards, >>>> Sergey >>>> >>>> >>>> >>>> -- >>>> View this message in context: >>>> >>>>http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/counter >>>>s-replication-awful-performance-tp7583993.html >>>> Sent from the >> >>> cassandra-user@.apache >> >>> mailing list archive at >>>> Nabble.com. >>>> >>> >>> >>> >>> -- >>> >>> Learn More: SQI (Social Quality Index) - A Universal Measure of Social >>> Quality >> >> >> >> >> >>-- >>View this message in context: >>http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/counters- >>replication-awful-performance-tp7583993p7583996.html >>Sent from the > cassandra-user@.apache > mailing list archive at >>Nabble.com. > > > 'Like' us on Facebook for exclusive content and other resources on all > Barracuda Networks solutions. > > Visit http://barracudanetworks.com/facebook -- View this message in context: http://cassandra-user-incubator-apache-org.3065146.n2.nabble.com/counters-replication-awful-performance-tp7583993p7584000.html Sent from the cassandra-u...@incubator.apache.org mailing list archive at Nabble.com.
